Pipe Size Calculator
Calculate the minimum pipe diameter for a given flow rate and maximum velocity. Supports copper, PEX, CPVC, and PVC.
Ad Space (horizontal)
GPM
Gallons per minute — total demand from all fixtures on this line
Material affects friction loss and max velocity
ft/s
Design velocity limit — 8 ft/s is standard for cold water
Related Calculators
Water FlowPlumbing
Calculate water flow rate from pipe diameter and velocity, or velocity from flow rate and diameter. Includes Reynolds number and flow type.
Water PressurePlumbing
Calculate pressure loss from elevation changes, pipe friction, and fittings. Determine available pressure at the fixture.
Fixture UnitsPlumbing
Count drainage and water supply fixture units (DFU/WSFU) to size drain and supply lines per plumbing code.
Ad Space (rectangle)